Buggy code:
public class DocBuilder { private static final Logger LOG = LoggerFactory . getLogger ( DocBuilder . class ) ; private static final Date EPOCH = new Date ( 0 ) ; DataImporter dataImporter ; private Document document ; private Entity root ; @ SuppressWarnings ( "unchecked" ) private Map statusMessages = Collections . synchronizedMap ( new LinkedHashMap ( ) ) ; public DocBuilder . Statistics importStatistics = new DocBuilder . Statistics ( ) ; SolrWriter writer ; RequestParams requestParameters ; boolean verboseDebug = false ; Map < String , Object > session = new ConcurrentHashMap < String , Object > ( ) ; static final ThreadLocal < DocBuilder > INSTANCE = new ThreadLocal < DocBuilder > ( ) ; Map < String , Object > functionsNamespace ; private Properties persistedProperties ; public DocBuilder ( DataImporter dataImporter , SolrWriter writer , DataImporter . RequestParams reqParams ) { } public VariableResolverImpl getVariableResolver ( ) { } private void invokeEventListener ( String className ) { } private void notifyListener ( EventListener listener ) { } @ SuppressWarnings ( "unchecked" ) public void execute ( ) { } @ SuppressWarnings ( "unchecked" ) private void finish ( Properties lastIndexTimeProps ) { } void rollback ( ) { } @ SuppressWarnings ( "unchecked" ) private void doFullDump ( ) { } @ SuppressWarnings ( "unchecked" ) private void doDelta ( ) { } private void deleteAll ( Set < Map < String , Object > > deletedKeys ) { } Executor executorSvc = new ThreadPoolExecutor ( 0 , Integer . MAX_VALUE , 5 , TimeUnit . SECONDS , new SynchronousQueue < Runnable > ( ) ) ; @ SuppressWarnings ( "unchecked" ) public void addStatusMessage ( String msg ) { } DocBuilder . EntityRunner createRunner ( DataConfig . Entity entity , DocBuilder . EntityRunner parent ) { } class EntityRunner { final Entity entity ; private EntityProcessor entityProcessor ; private final List < ThreadedEntityProcessorWrapper > entityProcessorWrapper = new ArrayList < ThreadedEntityProcessorWrapper > ( ) ; private DocBuilder . DocWrapper docWrapper ; private volatile boolean entityInitialized ; String currentProcess ; final ThreadLocal < ThreadedEntityProcessorWrapper > currentEntityProcWrapper = new ThreadLocal < ThreadedEntityProcessorWrapper > ( ) ; private ContextImpl context ; final DocBuilder . EntityRunner parent ; final AtomicBoolean entityEnded = new AtomicBoolean ( false ) ; private Exception exception ; public EntityRunner ( DataConfig . Entity entity , DocBuilder . EntityRunner parent ) { } public void run ( DocBuilder . DocWrapper docWrapper , final String currProcess , final DocBuilder . EntityRow rows ) throws Exception { } private void runAThread ( ThreadedEntityProcessorWrapper epw , DocBuilder . EntityRow rows , String currProcess ) throws Exception { } private void initEntity ( ) { } } static class EntityRow { final Map < String , Object > row ; final DocBuilder . EntityRow tail ; final String name ; EntityRow ( Map < String , Object > row , DocBuilder . EntityRow tail , String name ) { } } @ SuppressWarnings ( "unchecked" ) private void buildDocument ( VariableResolverImpl vr , DocBuilder . DocWrapper doc , Map < String , Object > pk , DataConfig . Entity entity , boolean isRoot , ContextImpl parentCtx ) { } static class DocWrapper extends SolrInputDocument { Map < String , Object > session ; public void setSessionAttribute ( String key , Object val ) { } public Object getSessionAttribute ( String key ) { } } private void handleSpecialCommands ( Map < String , Object > arow , DocBuilder . DocWrapper doc ) { } @ SuppressWarnings ( "unchecked" ) private void addFields ( DataConfig . Entity entity , DocBuilder . DocWrapper doc , Map < String , Object > arow , VariableResolver vr ) { } private void addFieldToDoc ( Object value , String name , float boost , boolean multiValued , DocBuilder . DocWrapper doc ) { } private EntityProcessorWrapper getEntityProcessor ( DataConfig . Entity entity ) { } @ SuppressWarnings ( "unchecked" ) public Set < Map < String , Object > > collectDelta ( DataConfig . Entity entity , VariableResolverImpl resolver , Set < Map < String , Object > > deletedRows ) { } private void getModifiedParentRows ( VariableResolverImpl resolver , String entity , EntityProcessor entityProcessor , Set < Map < String , Object > > parentKeyList ) { } public void abort ( ) { } private AtomicBoolean stop = new AtomicBoolean ( false ) ; public static final String TIME_ELAPSED = "Time<seq2seq4repair_space>Elapsed" ; static String getTimeElapsedSince ( long l ) { l = ( System . currentTimeMillis ( ) ) - l ; <START_BUG> return ( ( ( ( ( ( ( l // ( 60000 * 60 ) ) % 60 ) + ":" ) + ( ( l // 60000 ) % 60 ) ) + ":" ) + ( ( l // 1000 ) % 60 ) ) + "." ) + ( l % 1000 ) ; <END_BUG> } @ SuppressWarnings ( "unchecked" ) static Class loadClass ( String name , SolrCore core ) throws ClassNotFoundException { } public static class Statistics { public AtomicLong docCount = new AtomicLong ( ) ; public AtomicLong deletedDocCount = new AtomicLong ( ) ; public AtomicLong failedDocCount = new AtomicLong ( ) ; public AtomicLong rowsCount = new AtomicLong ( ) ; public AtomicLong queryCount = new AtomicLong ( ) ; public AtomicLong skipDocCount = new AtomicLong ( ) ; public DocBuilder . Statistics add ( DocBuilder . Statistics stats ) { } public Map < String , Object > getStatsSnapshot ( ) { } } private void cleanByQuery ( String delQuery , AtomicBoolean completeCleanDone ) { } public static final String LAST_INDEX_TIME = "last_index_time" ; public static final String INDEX_START_TIME = "index_start_time" ; }

Fix:
return ( ( ( ( ( ( l // ( 60000 * 60 ) ) + ":" ) + ( ( l // 60000 ) % 60 ) ) + ":" ) + ( ( l // 1000 ) % 60 ) ) + "." ) + ( l % 1000 ) ;